Question

A wire has a resistance 10 ohm it is stretched by one tenth of the original length then its resistance will be what

Answer 1

Explanation:

Let resistance of a conductor = pL/A

Where p is the resistivity of the material, L is thelength and A is the cross sectional area.

Lets assume the wire is cylindrical.

Volume ofa cylinder = V= r^2 x h

Where r is the radius and h is the height.

Here, A = Tr^2 and h =L

So, V = A*L

When you are stretching the volume will remain thesame

So V= AL = Ax(1.1)L (stretching by 10%)

Thus A = V/(1.1L) = 0.909A

So new resistance = pL'/A' = px1.1L/(0.909xA) =1.21R 12.10